Patent Number: 6,166,726

Title: Circuit for driving a liquid crystal display

Abstract: A power supply applies a power-supply voltage VDD to operate an LCD driver circuit. A booster circuit increases the power-supply voltage VDD, generating an LCD-driving voltage VLDC. When the power-supply voltage VDD is equal to or higher than a predetermined voltage, a power-supply voltage detecting circuit outputs the LCD-driving voltage VLCD to a switch circuit. The switch circuit disconnects the line for applying the voltage VLCD, from the line for applying a reference voltage GND. When the power-supply voltage VDD is lower than the predetermined voltage, the power-supply voltage detecting circuit outputs an indefinite voltage to the switch circuit. In this case, the switch circuit short-circuits the line for applying the voltage VLCD, to the line for applying the reference voltage GND. This prevents undesired phenomena, such as flickering, from occurring on the screen of the liquid crystal display, even if the application of power-supply voltage VDD is interrupted.

Inventors: Uchida; Hideaki (Sagamihara, JP), Ohhashi; Kouji (Yokohama, JP)

Assignee: Kabushiki Kaisha Toshiba

International Classification: G09G 3/36 (20060101); G09G 003/36 (); G09G 005/00 ()

Expiration Date: 12/26/2017